Impacting tool



July 13 1926. 1,592,695

F. w. JACKSON nmcnue TOOL Filed Dec. 11, 1922 Patented July 13, 1926. V

UNITED STATES 1 1,592,695 PATENT OFFICE.

FRANK W. JACKSON, OF CHICAGO, ILLINOIS, ASSIGNOR TO MAXSON CORPORATION, OI

CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

IMPACIING TOOL.

Application filed December My invention relates to impacting tools employing hammer elements to which operating force is applied through the intermediation of air or other cushioning means.

In accordance with my invention the ham mer element is of compound formation. being formed of two relatively movable members, one initially receiving the impacting force and the other applying the same to the work. there being a cushion between the two members through which the impacting force is transmitted. The impacting member of the hammer is preferably withdrawn by means of retractile force exerted through another cushion intervening between both members of the hammer.

The member of the hammer which initial 1y receives the impacting force is desirably in the form of a piston and the complemental. member is in the form of a cylinder in which the piston may reciprocate. The cylinder is preferably substantially air tight except at the mid zone thereof where it is provided with air ports or passages. The air trapped between the pistonand both ends of the cylinder forms cushions upon both sides of the piston through one of whichthe impacting force is transmitted when the piston is moved in a hammer striking direction and through the other of which the retractile force is exerted when the piston is moved in a hammer withdrawing direction. The final portion of the movement of the striking member of the hammer is desirably effected by the momentum thereof, the striking member of the hammer then moving far enough beyond the piston to unseal the cylinder to permit the momentum of the striking hammer member to be fully effective.

I will explain my invention more fully by reference to the accompanying drawing in which Fig. 1 is a view in elevation of a tool constructed in accordance with the preferred embodiment of the invention, parts being shown in section; Fig. 2 is another view in elevation, taken at right angles to the direction in which Fig. 1 is taken, with parts shown in section and parts broken away; and Fig. 3 is a sectional view on line 33 of Fig. 1 but on a smaller scale.

Like parts are indicated by similar characters'of reference throughout the different figures.

The hammer illustrated comprises a cylinder 1 and a piston 2 reciprocable within or 11, 1922. Serial No. 606,179.

with reference to the cylinder. The impacting force is initially applied to one of the hammer members, preferably the piston 2 the other member striking the blow. Both of the hammer members 1 and 2 are movable w1th respect to each other and also with respect to the cylindrical casing or cage 3 which encloses them. The casing carries a ring 4 within its interior, this ring being assembled with the casing by means of keys that are received within arcuate notches formed upon the interior of the casing and through which assembling screws 6 are passed into the ring. One end of the cylinder 1 has sliding fit within the ring 4 that serves as a guide that takes part in limiting the cylinder to rectilineal movement. The other end rectly engage the inner surface of the casing 3 whereby the casing and the ring 4 therein .co-operate to limit the cylinder to rectilineal movement along the cylinder axis. The cylinder 1 is preferably substantially air tight except at its mid zone where ports 8 are sealed by the piston, being unsealed in the final movement of the cylinder 1 in a striking direction and a withdrawing direction successively occurring during the reciprocations of. the piston that may be effected in any suitable way a but preferably by the mechanism illustrated and presently to be fully described;

The impacting end of the cylinder may be formed with a striking head 9 aligned with the axial opening in the outer end of the trapping of the air between the reciprocating cylinder: 1 and the outer guide cylinder 3 that would render the movement of the cylinder sluggish.

The casing 3 desirably has an enlarged continuation 16. Tie rods 17 are passed through the end wall 18 of the casing extension 16 and through the flange 19 slipped upon the smaller and outer end of the cylprovided which are intermittently.

of the cylinder is formed with ribs 7 that di inder 3 into engagement with the shoulder as illustrated in Fig. 1. Nuts 20 upon the tie rods serve to clamp the casing sections together, the casing extension 16 being thereby clamped against the, flange 21 slipped upon the smaller and inner end of the cylinder 3 into engagement with the shoulder as illustrated in Fig. 1. Thus, the various parts of the casing of the implement are readily assembled and may be readily taken apart.

The casing extension 16 carries two aligned roller bearings 22 within the casing and which receive the main driving shaft 23, illustrated herein as a crank shaft, there being a crank handle 24 by which this shaft may be turned to render the implement manually operable although the invention is not to be thus limited; The crank shaft 23 can ries a spur gear 25 in mesh with a spur pinion 26 mounted on a countershaft 27 which is carried by aligned roller bearings 28 that are also carried upon and within the casing extension 16. A heavy crank disc 29 is mounted upon the countershaft' 27 to serve as a fly wheel in addition to its function of effecting the reciprocation of the piston 2, for which latter purpose the crankdisc is coupled with the piston stem 30 by means of a pitman or connecting rod 31. The upper end of this connecting rod is pivoted to a crank pin 29 projecting from the side of the crank disc or fly wheel29', and' the lower end is suitably pivoted to the upper end of the piston stem 30. It will be observed from Fig. 2 that intermediate these points of pivotal connection the connecting rod is bowed outwardlv to operate around the main shaft 23. Rotary motion imparted to the shaft 23 by means ofj the crank handle 24 is multiplied by the gears 25 andf26 to effect rapid reciprocation of the piston 2. This piston forces movement of the cylinder therewith through the intermediation of the cushion, the trapped air, that is between the piston and the impacting end of the cylinder. The cylinder 1' is massive to enable the movement imparted to itby the; piston to be continued by momentumand by'the compressed body of air when the piston reaches the end of its stroke, the piston then uncovering the ports 8 to permit the momentum ofthe-cy linder to have full ef fect. Similarly, the cylinderis retracted in the reverse movement of the piston. The handle 32 may also be assembled with the casing extension 16' by means of brackets 33 clamped in position by the nuts 20 at the casing end wall 18.

While I have herein shown. and; particularly describedthe preferred embodiment; of myi-nvention I do not wish to be limited to the precise details. of construction shown'as, changes may readily be-mad'e without departing from the spirit of my invention,

but having thus described my invention I claim as new and desire to secure by Letters Patent the following 1. In aportable, hand-driven hammer for drilling concrete and performing like operations, the combination of a casing, a main shaft journalled in the upper end of said casing, a hand-operated crank on the outer end of said main shaft, a countershaft journalled in said casing above said main shaft, a large spur gear on said main shaft driving a spur pinion on said countershaft at an increased rate of speed, a fly wheel mounted on said countershaft within said casing, a crank element rotating with said fly Wheel, guide surfaces in the lower end of said casing, a pair of pneumatic members comprising anouter cylinder member reciprocably supported by said guide surfaces and comprising an inner piston member'recipro cable in said cylinder member, a connecting rod pivotally connected at its upper end to said crank element and at its lower end to one of said pneumatic members, said connecting rod comprising a bowed portion intermediate its ends for operating aroundthe transversely extending main shaft, and means on the lower end of said casing adapted'to support an impact member for receiving the impact blows from one of the aforesaid pneumatic members.

2. In a portable. hand-driven reciprocating hammer, the combination of a casing, 21 main shaft journalled in the upper part of said casing, a hand-operating crank mounted on the outer end of said main shaft, a countershaft journalled in said casing, a large spur gear on said main shaft driving a spur pinion on said count-ershaft, a fly wheel mounted on said countershaft within said casing, a crank element rotating with said fly wheel, guide surfaces in the lower end of said casing, a pair of pneumatic members comprising an outer cylinder member reciprocably supported by said guide surfaces and comprising an inner piston member reciprocable in said cylinder memher, a connecting rod pivotally connected at its upper end to said crank element and atitslower end to one of said pneumatic members. and an impact member supported at the lower end of said casing adapted to receive impact blows from one of the aforesaid pneumatic members.

3. In a portable. hand-driven reciprocating hammer for drilling concrete and the like. the combination of a. casing, a. main shaft journalled in the upper part of. said casing. a hand-operating crank mounted on the outer end of said main shaft, a countershaft journalled in said casing above said main shaft, a large spur gear on said main shaft driving a spur pinion on said countershaft at an increased rate of speed, a fly wheel mounted on said countershaft within said casing, a crank element rotating With said fly wheel, guide surfaces in the lower end of said casing, a pair of pneumatic members comprising an outer cylinder member reciprocably supported by said guide surfaces and comprising an inner piston member recipr cable in said cylinder member, a connecting rod pivotally connected at its upper end to said crank element and at its lower end to one of said pneumatic mem bers, said connecting rod comprising a bowed portion intermediate its ends for operating around the transversely extending main shaft, an impact member reciprocably supported in the lower end of said casing and adapted to receive blows from the impact end of one of said pneumatic members, and an air port in said cylinder member admitting air thereto, the impulse of the crank-reciprocated member being transmitted to the other pneumatic member by air pressure therebetween. said crank-reciprocated pneumatic member having a shorter operating stroke than said impacting pneu' matic member whereby when said crankdriven pneumatic member reaches the end of its operating stroke the impacting pneumatic member continues to move under the impulse of the compressed air before striking the impact member supported in the end of the casing.

4. In a portable, hand-driven reciprocatsaid fly wheel, a guide sleeve constructed as I a unit and removably supported at the lower end of said casing, a pair of pneumatic members r ciprocably supported in said guide sleeve and comprising a cylinder member and a piston member therein, a connecting rod pivotally connected at its upper end to said crank element and at its lower end to said piston member, said connecting rod comprising a boweo portion intermediate its ends for operating around the transversely extending main shaft, an impacting element adapted to receive blows from said cylinder member, and pin and socket means cooperating with said impacting element to permit its axial reciprocation, but to prevent its rotation relative to said casing.

In witness whereof, I hereunto subscribe my name this 6th day of December A. D., 1922.

FRANK W. JACKSON. 

